libmagic example usage in C#

LibMagic.csproj

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net8.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
  </PropertyGroup>

</Project>

Program.cs

// $ c:~/playground/LibMagic>dotnet run -- joy.png
// image/png\012- application/octet-stream; charset=binary

using System.Runtime.InteropServices;

namespace LibMagic;

class Program
{
    enum MagicFlags
    {
        MAGIC_DEBUG = 1,
        MAGIC_CONTINUE = 32,
        MAGIC_ERROR = 512,
        MAGIC_MIME = 1040
    };

    [DllImport("magic")]
    public static extern IntPtr magic_open(int flags);

    [DllImport("magic")]
    public static extern void magic_close(IntPtr handle);

    [DllImport("magic", CallingConvention = CallingConvention.Cdecl)]
    public static extern int magic_load(IntPtr handle, IntPtr magic_file);

    [DllImport("magic", CallingConvention = CallingConvention.Cdecl)]
    public static extern IntPtr magic_file(IntPtr handle, string input_file);

    static void Main(string[] args)
    {
        IntPtr joy = magic_open((int)(MagicFlags.MAGIC_CONTINUE | MagicFlags.MAGIC_ERROR | MagicFlags.MAGIC_MIME));

        magic_load(joy, IntPtr.Zero);

        Console.WriteLine(Marshal.PtrToStringAnsi(magic_file(joy, args[0])));

        magic_close(joy);
    }
}